﻿using System;
using System.Collections;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Reflection;
using System.Text;

namespace Common
{
    public static class ListToTable
    {
        //public static DataTable ToDataTable<T>(IEnumerable<T> collection)
        //{
        //    var props = typeof(T).GetProperties();
        //    var dt = new DataTable();
        //    dt.Columns.AddRange(props.Select(p => new DataColumn(p.Name, p.PropertyType)).ToArray());
        //    if (collection.Count() > 0)
        //    {
        //        for (int i = 0; i < collection.Count(); i++)
        //        {
        //            ArrayList tempList = new ArrayList();
        //            foreach (PropertyInfo pi in props)
        //            {
        //                object obj = pi.GetValue(collection.ElementAt(i), null);
        //                tempList.Add(obj);
        //            }
        //            object[] array = tempList.ToArray();
        //            dt.LoadDataRow(array, true);
        //        }
        //    }
        //    return dt;
        //}


        /// <summary>
        /// Convert a List{T} to a DataTable.
        /// </summary>
        public static DataTable ToDataTable<T>(List<T> items)
        {
            var tb = new DataTable(typeof(T).Name);

            PropertyInfo[] props = typeof(T).GetProperties(BindingFlags.Public | BindingFlags.Instance);

            foreach (PropertyInfo prop in props)
            {
                Type t = GetCoreType(prop.PropertyType);
                tb.Columns.Add(prop.Name, t);
            }

            foreach (T item in items)
            {
                var values = new object[props.Length];

                for (int i = 0; i < props.Length; i++)
                {
                    values[i] = props[i].GetValue(item, null);
                }

                tb.Rows.Add(values);
            }

            return tb;
        }

        /// <summary>
        /// Determine of specified type is nullable
        /// </summary>
        public static bool IsNullable(Type t)
        {
            return !t.IsValueType || (t.IsGenericType && t.GetGenericTypeDefinition() == typeof(Nullable<>));
        }

        /// <summary>
        /// Return underlying type if type is Nullable otherwise return the type
        /// </summary>
        public static Type GetCoreType(Type t)
        {
            if (t != null && IsNullable(t))
            {
                if (!t.IsValueType)
                {
                    return t;
                }
                else
                {
                    return Nullable.GetUnderlyingType(t);
                }
            }
            else
            {
                return t;
            }
        }
    }
}
